Extreme ultraviolet lithography (EUV), also known as soft x-ray projection lithography, has begun to replace deep ultraviolet lithography for the manufacture of 0.13 micron, and smaller, minimum feature size semiconductor devices. EUV systems operate by reflection instead of transmission of light. Through the use of a series of mirrors, or lens elements, and a reflective element, or mask blank, coated with a non-reflective absorber mask pattern, patterned actinic light is reflected onto a resist-coated semiconductor wafer.
Conventional EUV blank processes may include, for example, a 152 mm×152 mm blank reticle being placed into a coating tool to apply various coatings. As configured, the square reticle is sandwiched within a carrier assembly (e.g., a 300 mm carrier assembly) to enable the reticle to be transferred through the coating tool like a 300 mm wafer. The carrier assembly may include a carrier base, the reticle blank, and a carrier shield.
During processing, every time the reticle blank is transported into the coating tool, the elements of the carrier assembly are brought together and separated apart. This process involves multiple lifts and clamps for separating the carrier base and the carrier shield so a reticle can be placed therebetween. The lifts can be extended or retracted to open or close the carrier assembly. However, this approach is undesirable because multiple lifting and clamping components are provided near the reticle, thus increasing the possibility particles are generated. Furthermore, current techniques undesirably place the reticle in an enclosure, as opposed to directly in a clean FI-robot mini environment, use one of the few loadport positions available on the front of the FI, and reduce accuracy placement for the carrier assembly because the FI needs to pick-up the carrier assembly from multiple modules, thus increasing the likelihood of a placement error.